LINCOLN CITY — In the hierarchy of roadwork, Mark Noah’s job may be the dirtiest.

Caked from hardhat to toe in a layer of dust and mud, Noah nimbly adjusted the levers and pedals of his 35-ton machine to nudge its tracked feet and seven-story mast into position.

Like surgeons poised over an operating table, the six-member work crew from Scheffler Northwest guided a 5,000-pound bit — the business end of the giant drilling contraption — between a fragile row of engineer tapes.

Construction of the $19 million Nelscott Highway Improvement Project in Lincoln City is underway, and the most apparent sign of progress is the boring endeavor that towers over the stream of nearby traffic on Highway 101.